The consistency of the current battery cells is not good enough, and it needs to be improved through 셀 밸런싱. Therefore, cell balancing is ultimately to solve the shortcomings of the battery cells, and it is a means of compensation.
목차
What is cell balancing?
Lithium-ion power battery packs are generally composed of several single cells connected in series or in parallel. There are two common types of lithium-ion batteries: 삼원계 리튬 배터리 and lithium iron phosphate battery. Cell balancing refers to the use of differential currents for different cells in a series battery pack.
During the use of the battery, the cells in series can be activated and charged through cell balancing, so that the capacity of the cells can be maximized to ensure that the energy of each battery unit is available.
Active cell balancing and passive cell balancing
Cell balancing is divided into active cell balancing and passive cell balancing. Passive cell balancing generally discharges the battery with higher voltage through resistance discharge, releases the power in the form of heat, and buys more charging time for other batteries. In this way, the power of the whole system is limited by the battery with the least capacity.
During the charging process, lithium batteries generally have a charging upper limit protection voltage value. When a certain string of batteries reaches this voltage value, the lithium battery protection board will cut off the charging circuit and stop charging. If the charging voltage exceeds this value, which is commonly known as overcharging, the lithium battery may burn or explode.
Therefore, the advantages of passive cell balancing are low cost and simple circuit design. The disadvantages are that cell balancing is performed based on the lowest remaining battery capacity, which cannot increase the capacity of a battery with a small residual capacity, and 100% of the balanced power is wasted in the form of heat. Lithium battery protection boards generally have an overcharge protection function to prevent the battery from overcharging.
Active cell balancing is equalized by means of power transfer, with high efficiency and low loss. Different manufacturers have different methods, and the equalizing current also ranges from 1 to 10 A. Many active cell balancing technologies currently on the market are immature, resulting in battery over-discharge and accelerated battery attenuation.
Most of the active cell balancing on the market use the principle of voltage transformation, relying on expensive chips from chip manufacturers. Moreover, in addition to the cell balancing chip, this method also requires peripheral components such as expensive transformers, which are large in size and high in cost.
Passive cell balancing is suitable for small-capacity, low-series lithium battery pack applications, and active cell balancing is suitable for high-series, large-capacity power lithium battery pack applications. For BMS, in addition to the very important balance function, the balance strategy behind it is even more important.
Why do lithium-ion power batteries need cell balancing?
As the number of charge and discharge increases between the cells, the voltage difference gradually enlarges
● During the production process of battery cell, there will be slight differences between different cells. ● Used in a long-term fast charging environment, the voltage difference between the cells will gradually increase. ● Battery management system (BMS), as the brain and hands of the power battery, collects various data, calculates battery state of charge, health status and other parameters, evaluates the performance of each battery cell, and takes emergency measures in time when the battery cell is in a dangerous situation Control logic to protect vehicle driving safety. ● BMS calculates the state of charge by collecting various data.
Small capacity battery cell directly affect the actual battery life
● The electric vehicle battery pack of the battery swapping version is composed of multiple lithium iron phosphate or ternary cells connected in series. Due to the slight differences in the production process of different cells, the voltage of the cells will inevitably gradually vary under the condition of long-term use of high current.
● According to the short plate effect, the battery cells with small capacity directly affect the actual battery life. When using the battery, the cells with small capacity are the first to reach the cut-off voltage, which is easy to cause overcharging and over-discharging. This not only affects the user experience, but also has a certain impact on battery life and safety.
● In order to avoid the unbalanced trend of batteries caused by differences in individual voltage and capacity, etc., the battery management system (BMS) is required to start balancing the batteries.
Characteristics of lithium iron phosphate battery
● If the vehicle is in the fast charging operation state for a long time, the pressure difference between the battery cells will be too large, resulting in a decrease in the cruising range of the vehicle.
● Therefore, every time the battery swapping version of the vehicle goes to the EV 배터리 교체 station to change batteries, the battery swapping station will test and maintain the battery pressure difference to ensure that the battery voltage difference is within a reasonable range and extend the battery life.
In general, cell balancing can change the state of the battery. The purpose of cell balancing is to change the state of each cell of the battery to the same level, so that the battery will be more durable. So the meaning of cell balancing is:
● Improve the consistency of the single cell, so that each single cell maintains the same state during normal use; ● Slow down battery deterioration and prolong battery life; ● Prevent thermal runaway caused by long-term overcharge and overdischarge of individual batteries.
The impact of fast charging on battery and the advantages of battery swap
Long-term fast charging is likely to cause premature aging of the battery, and a severely attenuated battery may experience jumps in battery life:
● The jump of high cruising range is manifested as a rapid decline in cruising range within a short distance; ● The mileage jumps in the middle, and the mileage fluctuates up and down in the 200-kilometer cruising state; ● When the jump of low mileage is serious, it may cause the vehicle to be powered off and unable to start.
Battery swapping has the following advantages:
● The swap station has the conditions for cell balancing. The power station is monitored 24 hours a day, and the charging process is supervised throughout, so that the abnormal information of the battery can be monitored in time, the abnormal battery is frozen and the battery is balanced, and the battery is not transferred until the balance is completed and the test is normal.
● Cell balancing is time-consuming, labor-intensive and costly. It takes a lot of time to balance the battery each time. After there is no problem with the cell balancing, the battery swapping station will continue to track and detect the use of the battery, which is time-consuming, labor-intensive and costly. The battery swap vehicle battery balancing is completed by the battery swapping station.
● Under the normal use of the vehicle, you can enjoy higher quality battery service performance.
안녕하세요, 독자 여러분, 저는 글쓰기에 대한 열정과 배터리 스와핑 업계에 대한 풍부한 경험을 가진 작가라고 자신 있게 소개합니다. 저는 전자공학 학사 학위를 받았으며, 이전에 유명 파워 배터리 회사에서 배터리 엔지니어로 근무하면서 설계부터 운영 구현까지 다양한 오토바이 스와핑 스테이션 프로젝트에 적극적으로 참여하고 주도했습니다.
수년 동안 저는 스와핑 기술, 비즈니스 모델 및 시장 동향을 적극적으로 탐구하고 광범위하게 연구했습니다. 실무 경험을 통해 스테이션 계획, 장비 선정 및 운영 관리의 다양한 측면에 적극적으로 기여하면서 귀중한 통찰력을 축적해 왔습니다.
배터리 스와핑 분야에서 저의 통찰력과 경험을 공유할 수 있기를 간절히 기대하고 있습니다. 저의 글이 빠르게 진화하는 이 산업을 더 잘 이해하고 의사결정에 귀중한 통찰력을 제공하는 데 도움이 될 것이라 믿습니다. 배터리 스와핑의 세계를 함께 탐험하는 흥미진진한 여정을 시작합시다!
리튬 이온 전력 배터리에 셀 밸런싱 적용
What is cell balancing?
Lithium-ion power battery packs are generally composed of several single cells connected in series or in parallel. There are two common types of lithium-ion batteries: 삼원계 리튬 배터리 and lithium iron phosphate battery. Cell balancing refers to the use of differential currents for different cells in a series battery pack.
During the use of the battery, the cells in series can be activated and charged through cell balancing, so that the capacity of the cells can be maximized to ensure that the energy of each battery unit is available.
Active cell balancing and passive cell balancing
Cell balancing is divided into active cell balancing and passive cell balancing. Passive cell balancing generally discharges the battery with higher voltage through resistance discharge, releases the power in the form of heat, and buys more charging time for other batteries. In this way, the power of the whole system is limited by the battery with the least capacity.
During the charging process, lithium batteries generally have a charging upper limit protection voltage value. When a certain string of batteries reaches this voltage value, the lithium battery protection board will cut off the charging circuit and stop charging. If the charging voltage exceeds this value, which is commonly known as overcharging, the lithium battery may burn or explode.
Therefore, the advantages of passive cell balancing are low cost and simple circuit design. The disadvantages are that cell balancing is performed based on the lowest remaining battery capacity, which cannot increase the capacity of a battery with a small residual capacity, and 100% of the balanced power is wasted in the form of heat. Lithium battery protection boards generally have an overcharge protection function to prevent the battery from overcharging.
Active cell balancing is equalized by means of power transfer, with high efficiency and low loss. Different manufacturers have different methods, and the equalizing current also ranges from 1 to 10 A. Many active cell balancing technologies currently on the market are immature, resulting in battery over-discharge and accelerated battery attenuation.
Most of the active cell balancing on the market use the principle of voltage transformation, relying on expensive chips from chip manufacturers. Moreover, in addition to the cell balancing chip, this method also requires peripheral components such as expensive transformers, which are large in size and high in cost.
Passive cell balancing is suitable for small-capacity, low-series lithium battery pack applications, and active cell balancing is suitable for high-series, large-capacity power lithium battery pack applications. For BMS, in addition to the very important balance function, the balance strategy behind it is even more important.
Why do lithium-ion power batteries need cell balancing?
As the number of charge and discharge increases between the cells, the voltage difference gradually enlarges
● During the production process of battery cell, there will be slight differences between different cells.
● Used in a long-term fast charging environment, the voltage difference between the cells will gradually increase.
● Battery management system (BMS), as the brain and hands of the power battery, collects various data, calculates battery state of charge, health status and other parameters, evaluates the performance of each battery cell, and takes emergency measures in time when the battery cell is in a dangerous situation Control logic to protect vehicle driving safety.
● BMS calculates the state of charge by collecting various data.
Small capacity battery cell directly affect the actual battery life
● The electric vehicle battery pack of the battery swapping version is composed of multiple lithium iron phosphate or ternary cells connected in series. Due to the slight differences in the production process of different cells, the voltage of the cells will inevitably gradually vary under the condition of long-term use of high current.
● According to the short plate effect, the battery cells with small capacity directly affect the actual battery life. When using the battery, the cells with small capacity are the first to reach the cut-off voltage, which is easy to cause overcharging and over-discharging. This not only affects the user experience, but also has a certain impact on battery life and safety.
● In order to avoid the unbalanced trend of batteries caused by differences in individual voltage and capacity, etc., the battery management system (BMS) is required to start balancing the batteries.
Characteristics of lithium iron phosphate battery
● If the vehicle is in the fast charging operation state for a long time, the pressure difference between the battery cells will be too large, resulting in a decrease in the cruising range of the vehicle.
● Therefore, every time the battery swapping version of the vehicle goes to the EV 배터리 교체 station to change batteries, the battery swapping station will test and maintain the battery pressure difference to ensure that the battery voltage difference is within a reasonable range and extend the battery life.
In general, cell balancing can change the state of the battery. The purpose of cell balancing is to change the state of each cell of the battery to the same level, so that the battery will be more durable. So the meaning of cell balancing is:
● Improve the consistency of the single cell, so that each single cell maintains the same state during normal use;
● Slow down battery deterioration and prolong battery life;
● Prevent thermal runaway caused by long-term overcharge and overdischarge of individual batteries.
The impact of fast charging on battery and the advantages of battery swap
Long-term fast charging is likely to cause premature aging of the battery, and a severely attenuated battery may experience jumps in battery life:
● The jump of high cruising range is manifested as a rapid decline in cruising range within a short distance;
● The mileage jumps in the middle, and the mileage fluctuates up and down in the 200-kilometer cruising state;
● When the jump of low mileage is serious, it may cause the vehicle to be powered off and unable to start.
Battery swapping has the following advantages:
● The swap station has the conditions for cell balancing. The power station is monitored 24 hours a day, and the charging process is supervised throughout, so that the abnormal information of the battery can be monitored in time, the abnormal battery is frozen and the battery is balanced, and the battery is not transferred until the balance is completed and the test is normal.
● Cell balancing is time-consuming, labor-intensive and costly. It takes a lot of time to balance the battery each time. After there is no problem with the cell balancing, the battery swapping station will continue to track and detect the use of the battery, which is time-consuming, labor-intensive and costly. The battery swap vehicle battery balancing is completed by the battery swapping station.
● Under the normal use of the vehicle, you can enjoy higher quality battery service performance.
배터리 셀과 관련된 자세한 내용은 다음을 참조하세요. 프리즘 셀, 수소 연료 전지, NMC 셀 전압.